1. Field of the Invention
The present invention relates to a light detecting device.
2. Description of Related Art
A light sensor detects illumination intensity outside of a vehicle. The light sensor is mounted to a dashboard of a compartment of the vehicle, or is arranged in a casing of a rain sensor for detecting raindrop when the rain sensor is mounted to a windshield of the vehicle.
JP-A-2003-504270 corresponding to U.S. Pat. No. 6,831,288 discloses a light sensor. The light sensor is arranged in the same casing as a rain sensor, and the light sensor is located inside of the rain sensor in the casing. Visible light passes through a lens of the light sensor, and infrared light passes through a lens of the rain sensor. However, a detection accuracy of the rain sensor may be decreased, due to light transmitted or reflected by the lens of the light sensor.
JP-A-2003-254897 corresponding to US 2003/0160158 A1 discloses a light sensor. The light sensor is arranged in an unused space of a casing of a rain sensor. Thus, light transmitted or reflected by a lens of the light sensor is restricted from affecting a detection accuracy of the rain sensor.
However, plural lenses are arranged in the casing in a manner that a line connecting an entrance hole and a light receiving element is coincident with an optical axis of the lens of the light sensor. Therefore, the light sensor detects only light traveling from a predetermined area having an axis perpendicular to a windshield and a predetermined angle relative to the axis.
If a size of the lens is made larger so as to enlarge a viewing angle of the light sensor, a size of the casing may also have to be made larger. Further, assembling of the plural lenses may be complicated.